Evaluation of activity and potential for development of antimicrobial resistance to a new tinted 2% chlorhexidine gluconate/70% isopropyl alcohol film-forming sterile preoperative skin preparation.

OBJECTIVES: Chlorhexidine gluconate (CHG) is routinely used for skin antisepsis before surgery. Its activity may be affected by formulation ingredients and the presence of organic matter such as blood and proteins. This in vitro study was designed to evaluate the antimicrobial activity of a new CHG skin prep containing a film-forming copolymer, and detect its potential for developing resistance and the potential for cross-resistance to antibiotics after CHG exposure. METHODS: Antimicrobial activity was evaluated in the presence and absence of serum in an in vitro time-kill study. Emergence of resistance to CHG and cross-resistance with antibiotic procedures were performed in vitro using 10 repository isolates from eight species and eight clinical isolate strains equal to the repository isolate strains (four isolates, two resistant and two non-resistant per species). RESULTS: A 5 log10 reduction (99.999%) for all organisms was observed using the copolymer formulation. The activity remained unchanged in the presence of serum. The minimum inhibitory concentration (MIC) did not increase for any of the strains evaluated for emergence of resistance. In addition, there was no change in MIC related to cross-resistance observed for any of the organism/antibiotic combinations tested. CONCLUSIONS: These results suggest that the film-forming copolymer and the tint in the new CHG skin prep did not interfere with antimicrobial efficacy, even in the presence of an organic soil load, and that the tested formulations showed no potential for developing resistance or cross-resistance with antibiotics.

Prospective, randomized in vivo comparison of a dual-active waterless antiseptic versus two alcohol-only waterless antiseptics for surgical hand antisepsis.

BACKGROUND: This study aimed to demonstrate the value of adding an active level of a persistent antimicrobial agent, such as chlorhexidine gluconate (CHG), to an alcohol-based surgical hand antiseptic. METHODS: The persistence of 3 waterless, brushless alcohol-based surgical hand antiseptics, including one product containing CHG, was compared. The test products were applied a total of 12 times over 5 days. Samples of aerobic bacteria were collected on days 1 and 5, on both days immediately after drying and 6 hours later, using the glove juice technique. Relative suppression of regrowth was compared using t tests. RESULTS: Using an equivalence margin of 20%, the alcohol plus CHG product showed noninferiority to the alcohol-only products at all sampling points and, based on significantly lower bacterial regrowth (P = .026), superior persistence to the alcohol-only products after 6 hours of glove wear. CONCLUSIONS: Given the primary objective of surgical hand antisepsis of reducing resident skin flora for the duration of the surgical procedure, using an alcohol-based hand antiseptic containing CHG appears to be the most appropriate choice for maintaining microbial levels as low as possible for as long as possible.

Suppression of regrowth of normal skin flora under chlorhexidine gluconate dressings applied to chlorhexidine gluconate-prepped skin.

BACKGROUND: Catheter colonization and bloodstream infection during the first week after insertion of a central venous catheter have been shown to result from the patient's own skin flora. METHODS: The backs of 32 healthy subjects were prepped with a 2% chlorhexidine gluconate (CHG)/70% isopropyl alcohol antiseptic. Three dressings, 2 of which contained CHG, were placed on the prepped skin in a randomized design. Samples of aerobic bacteria were collected using the cup scrub method. Skin under the dressings was sampled by quadrant on days 1, 4, and 7. Relative suppression of regrowth was compared using an adjusted paired t test. RESULTS: Mean log counts were 3.2 log(10) colony-forming units (CFU)/cm(2) before antisepsis and 0.4 after antisepsis. Mean log counts obtained on days 1, 4, and 7 were 0.4, 0.3, and 0.5 log(10) CFU/cm(2) for the CHG gel; 0.4, 0.4, and 0.9 log(10) CFU/cm(2) for the CHG disk; and 0.9, 1.2, and 1.5 log(10) CFU/cm(2) for the Control, respectively. CONCLUSION: Skin flora was not completely eradicated during antisepsis, and bacterial regrowth occurred postantisepsis. The use of CHG dressings helped sustain a reduced bacterial count on the skin. The continuously releasing CHG gel maintained suppression to a greater extent than the CHG disk at 7 days (P = .01).